Deana Hanold, left, hands out anti-fracking information Tuesday evening in front of the Boulder Theater while an image of a skull and crossbones, along with the words “Ban Fracking!,” are projected onto the side of Boulder County Courthouse. Police cited David Paul with trespassing for beaming the images onto the county building.

An activist associated with the group Boulder County Protectors was cited by police Tuesday night for projecting the image of a skull and crossbones and the words “Ban Fracking!” onto the exterior wall of the old courthouse on the Pearl Street Mall.

Boulder County attorney Ben Pearlman, who police said directed them to issue the trespassing ticket, said the image and phrase violated the county’s building-use policy. But a legal expert with the American Civil Liberties Union said the man was within his constitutional rights.

“I think that it looks like this ticket was issued in retaliation for exercising his First Amendment rights,” said Mark Silverstein, ACLU of Colorado’s legal director.

Members of Boulder County Protectors, the group that hung an anti-fracking banner on the Flatirons last month, were protesting outside the Boulder Theater, 2032 14th St., during Boulder’s celebration of the 50th anniversary of the city’s open space program.

David Paul, 54, said he had set up his light projector in a friend’s truck outside the theater, at 2045 13th St. From there, he projected the image on the wall of the courthouse annex across the street.

Pearlman said the content of the message projected onto the wall was irrelevant to the decision to seek a police citation. “This is the county building and the county does not want swastikas or any other messages that they don’t want on those walls.”

He said the county does not allow images or phrases — political or otherwise — to be beamed onto the building, and the courthouse’s front lawn is the only place people can publicly gather to protest.